Neumann Taylor V, Kara Berra, Sargolzaeiaval Yasaman, Im Sooik, Ma Jinwoo, Yang Jiayi, Ozturk Mehmet C, Dickey Michael D
Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, NC 27695, USA.
Micromachines (Basel). 2021 Feb 1;12(2):146. doi: 10.3390/mi12020146.
We report a spray deposition technique for patterning liquid metal alloys to form stretchable conductors, which can then be encapsulated in silicone elastomers via the same spraying procedure. While spraying has been used previously to deposit many materials, including liquid metals, this work focuses on quantifying the spraying process and combining it with silicones. Spraying generates liquid metal microparticles (5 μm diameter) that pass through openings in a stencil to produce traces with high resolution (300 µm resolution using stencils from a craft cutter) on a substrate. The spraying produces sufficient kinetic energy (~14 m/s) to distort the particles on impact, which allows them to merge together. This merging process depends on both particle size and velocity. Particles of similar size do not merge when cast as a film. Likewise, smaller particles (<1 µm) moving at the same speed do not rupture on impact either, though calculations suggest that such particles could rupture at higher velocities. The liquid metal features can be encased by spraying uncured silicone elastomer from a volatile solvent to form a conformal coating that does not disrupt the liquid metal features during spraying. Alternating layers of liquid metal and elastomer may be patterned sequentially to build multilayer devices, such as soft and stretchable sensors.
我们报道了一种用于对液态金属合金进行图案化以形成可拉伸导体的喷雾沉积技术，然后可以通过相同的喷雾程序将其封装在有机硅弹性体中。虽然喷雾此前已被用于沉积包括液态金属在内的多种材料，但这项工作重点在于对喷雾过程进行量化，并将其与有机硅相结合。喷雾会产生液态金属微粒（直径约5μm），这些微粒穿过模板上的开口，从而在基板上产生具有高分辨率（使用工艺切割机制作的模板时分辨率约为300μm）的线路。喷雾产生足够的动能（约14m/s），使微粒在撞击时发生变形，从而使其合并在一起。这种合并过程取决于微粒的大小和速度。当以薄膜形式浇铸时，大小相似的微粒不会合并。同样，以相同速度移动的较小微粒（<1μm）在撞击时也不会破裂，不过计算表明，此类微粒在更高速度下可能会破裂。通过从挥发性溶剂中喷雾未固化的有机硅弹性体，可以包裹液态金属部件，形成保形涂层，该涂层在喷雾过程中不会破坏液态金属部件。液态金属和弹性体的交替层可以依次进行图案化，以构建多层器件，如柔软且可拉伸的传感器。
